@netlify/config/lib/utils/set.js

Netlify config module

import isPlainObj from 'is-plain-obj';
// Set a property deeply using an array of `keys` which can be either strings
// (object properties) or integers (array indices).
// Adds default values when intermediary properties are undefined or have the
// wrong type. Also extends arrays when they are too small for a given index.
// Does not mutate.
export const setProp = function (parent, keys, value) {
    if (keys.length === 0) {
        return value;
    }
    if (Number.isInteger(keys[0])) {
        return setArrayProp(parent, keys, value);
    }
    return setObjectProp(parent, keys, value);
};
const setArrayProp = function (parent, [index, ...keys], value) {
    const arrayParent = Array.isArray(parent) ? parent : [];
    const missingItems = index - arrayParent.length + 1;
    const normalizedParent = missingItems > 0 ? [...arrayParent, ...new Array(missingItems)] : arrayParent;
    const newValue = setProp(normalizedParent[index], keys, value);
    return [...normalizedParent.slice(0, index), newValue, ...normalizedParent.slice(index + 1)];
};
const setObjectProp = function (parent, [key, ...keys], value) {
    const objectParent = isPlainObj(parent) ? parent : {};
    const newValue = setProp(objectParent[key], keys, value);
    return { ...objectParent, [key]: newValue };
};